Propagation path response estimation and interference canceling using spread-spectrum pilot signal in multi-feeder link of haps

Abstract

A downlink interference is dynamically suppressed in a multi-feeder link of a same frequency between an aerial-floating type communication relay apparatus and plural gateway (GW) stations with a simple configuration. A plurality of pilot signals, which are spectrally spread using a plurality of spread codes orthogonal to each other, are transmitted and received between the relay communication station of the aerial-staying type communication relay apparatus and plural GW stations, a propagation path response between plural GW stations and an antenna for feeder link of the communication relay apparatus in a transmission signal band of the feeder link is estimated based on reception results in which the plural pilot signals are spectrally inverse-spread, plural weights respectively corresponding to the plural of GW stations are calculated based on the plural propagation path responses, and with respect to each of the plural GW stations, a signal to be transmitted and received via a directional beam corresponding to another GW station is multiplied by the weight corresponding to the other GW station and subtracted from a signal to be transmitted and received via the directional beam corresponding to the GW station.